13-5771 Mitzvah N-108
Negative Mitzvah 108– This is a negative commandment: do not slay ritually both a pure [kosher] animal and its young in one day.
Hafetz Hayim – As Scripture says: “And whether it is a cow or a ewe, you shall not slay it and its young both in one day” (Lev. 22:28). If someone transgressed and did ritually slay them, the meat is kosher [permissible]. The day follows the night [a day is reckoned from sunset to sunset]; therefore if a person ritually slew the mother-animal at the beginning of the night of the fourth day of the week, he should not slay the young until the beginning of the fifth day. But if he slew the mother-animal toward the end of the fourth day, he may ritually slay the young at the beginning of the night of the fifth. This is in effect, everywhere and in every time for both men and women.
This is not a law for vegetarians or vegans. The law is pretty straight forward; we are not permitted to kill a mother-animal and her young on the same day. If you make a mistake and do it, you have sinned, but the meat is still kosher and it is permitted to be eaten. A day,for the purpose of this law is not twenty-four hours from the first slaughter. One has to wait until the next sunset before the second animal can be killed.
It is interesting to me that there is no punishment listed for those who violate this law. I suppose that there is no point in wasting the meat as long as it has been killed properly, but the person who has killed mother-animal and her young on the same day clearly has no heart for the suffering of animals and has a pretty cruel attitude about his or her work. Just because one makes a living slaughtering animals for food, this does not allow that person to become cruel or indifferent. We are obligated by Jewish Law to alleviate the pain for animals.
There is a story about Rabbi Yehuda HaNasi who was walking on the street when a calf who was being led to slaughter ran from the man who bought her and hid under the Rabbi’s cloak and mooed mournfully. Rabbi Yehuda returned the calf to the owner saying to the calf, “Go, for this you were created.” The story concludes that Rabbi was afflicted with a horrible illness for this act of cruelty to the animal. He suffers for many years until he, from his sickbed, speaks up for some mice in his home. For this act of kindness, he was cured. Judaism takes kindness to animals very seriously. Caring for animals is the first step in learning kindness to other people.